A model system for evaluating the role of specific molecules on the mechanical properties of cartilage matrix will be developed. Using methods of gene transfection and RNA interference, decorin will be either overexpressed or suppressed in chondrocytes from young rabbits, and then these cells grown in culture to produce a tissue that can be mechanically tested. Comparing mechanical test results from normal tissue with the gene altered tissue will aid in defining the role decorin, and other candidate molecules, plays in the mechanical properties of chondrocyte matrix. The developed model will be a new way to study the structure/function relationships for cartilage matrix molecules, and to study the mechanisms of cartilage diseases such as osteoarthritis. Cartilage weakens in the OA disease process; the new method will help identify critical molecules that when damaged could lead to this weakening.